On the internet, there is tons of information on this topic. What is a tree data structure, why is it important, when do we need to use, etc. But there isn't a lot of places where you can find a js example on this topic. I will attach this example here. It can be also useful for me in the future. I've implemented it in an OOP way, hope anyone can understand it.

class Tree {
  constructor(value) {
    this.value = value;
    this.right = null;
    this.left = null;
  }


  addNode(value) {
    return {
      value,
      right: null,
      left: null
    }
  }

  addValue(value) {
    if (value === this.value) return;

    let current = this;

    while(current.value) {
      if (current.value < value) {
        if (current.right) {
          current = current.right
        }else {
          current.right = this.addNode(value)
          break;
        }
      }else {
        if (current.left) {
          current = current.left
        }else {
          current.left = this.addNode(value)
          break;
        }
      }
    }
  }
}

const tree = new Tree(20);

tree.addValue(10)
tree.addValue(20)
tree.addValue(40)
tree.addValue(25)
tree.addValue(14)

console.log(tree)

Response:

{
  value: 20,
  right: {
    value: 40,
    right: null,
    left: {
      value: 25,
      right: null,
      left: null
    }
  },
  left: {
    value: 10,
    right: {
      value: 14,
      right: null,
      left: null
    },
    left: null
  }
}

Traversal methods, you can find here ->